Bestatin (Ubenimex) dosing & administration
Natural dipeptide analogue aminopeptidase inhibitor with dual immunostimulatory and antitumor activity, approved in Japan as adjuvant cancer therapy
Written by Michael Carroll — Owner, Director of Research · Reviewed by the Peptide Initiative Research Team · Editorial standards
Dosing
How much do I take?
Oral: Taken by mouth as a capsule, tablet, or liquid.
Bioavailability Varies by compound — many peptides are largely broken down in the gut, so little reaches the blood intact; some small molecules absorb well.
Timing
Best time to take
Take Bestatin (Ubenimex) at the same time each day for consistent blood levels. Morning dosing with breakfast is often preferred, but follow your healthcare provider's specific instructions.
With food?
Bestatin (Ubenimex) can typically be taken with or without food. Taking it with a light meal may help reduce any GI discomfort. Avoid taking with grapefruit juice or high-fat meals unless specifically directed.
If stacking
Bestatin (Ubenimex) should be used as directed by your healthcare provider. If combining with other medications or supplements, discuss potential interactions with your provider. Avoid combining with compounds that have overlapping mechanisms unless specifically guided by a medical professional.
Adjusting your dose
Increase if
- You are being treated for pulmonary arterial hypertension under physician guidance and require higher LTA4H inhibition
- Your oncologist recommends dose escalation based on insufficient immune response markers
- You have tolerated the starting dose well and are transitioning to the standard therapeutic dose
Decrease if
- You experience persistent gastrointestinal side effects at the current dose
- Liver function tests show elevated transaminases above acceptable thresholds
- You develop significant skin reactions or allergic symptoms
Signs of right dose
- Stable or improving T-lymphocyte counts on blood work
- Maintenance of complete remission in AML patients
- Reduced frequency of infections during cancer treatment
- Normal liver function tests during treatment
Administration
How do I use it?
Reconstitution
What you need
Injection
Route
Bestatin (Ubenimex) is administered Oral (capsule)—no injection required
Best sites
Storage
Before reconstitution
Store Bestatin (Ubenimex) in the refrigerator at 36-46°F (2-8°C) in its original packaging. Protect from light and moisture. Do not freeze. Check the expiration date before use. Some formulations may be stored at room temperature for limited periods—check your specific product labeling.
After reconstitution
Once reconstituted, Bestatin (Ubenimex) should be kept refrigerated at 36-46°F (2-8°C) and used within the timeframe specified on your product labeling (typically 14-28 days). Label the vial with the reconstitution date. Do not use if the solution appears cloudy, discolored, or contains particles.
Signs of degradation — discard the vial
Sample daily schedule
Morning
30 mg (1 capsule) injection
Site: Oral — swallow whole with water
Take at the same time each day for consistent plasma levels. Can be taken with or without food. For AML maintenance, this is the standard once-daily regimen.
Safety
Is it safe?
Side effects
Commonly reported: Gastrointestinal discomfort, Skin rash or pruritus, Facial flushing, Fatigue
Less common: Elevated liver enzymes, Mild leukopenia
Stop and seek help if
- Severe allergic reaction (rash, swelling, difficulty breathing)
- Significant liver enzyme elevation (AST/ALT >3x upper limit of normal)
- Persistent or worsening side effects despite dose adjustment
- Disease relapse requiring change in treatment protocol
- Physician determines treatment goals have been achieved or treatment is no longer beneficial
Always consult with your healthcare provider before stopping bestatin, especially during cancer treatment. Abrupt discontinuation during AML maintenance therapy should only be done under medical supervision.
Flagged pairings
- Immunosuppressants (cyclosporine, tacrolimus) — Bestatin's immunostimulatory effects directly counteract immunosuppressive therapy. Avoid concurrent use or use only with careful immune monitoring.
- ACE inhibitors — Bestatin inhibits aminopeptidases involved in angiotensin metabolism, which may potentiate the hypotensive effects of ACE inhibitors. Monitor blood pressure closely if used together.
Published research
What the studies show
Tsukagoshi S · 1987
Bestatin works by blocking enzymes on immune cells, which lets important immune signals stick around longer and boost T-cell activity. When mice with cancer got bestatin combined with chemotherapy, they lived much longer than those getting chemo alone, showing the drug powerfully strengthens the body's cancer-fighting immune response.
Hiraoka A, Shibata H, Masaoka T · 1992
Leukemia patients taking 30 mg daily of bestatin showed major improvements in their natural killer cells and T-lymphocytes, the key soldiers of the immune system. These immune benefits stayed strong throughout treatment and helped patients better fight off their cancer while recovering from chemotherapy.
Ota K, Ogawa N · 1990
Bestatin jumpstarted the bone marrow's ability to recover after chemotherapy wiped it out, rebuilding immune cell numbers faster than normal. The drug specifically boosted CD4+ T-cells—the quarterbacks that coordinate immune attacks—making it a powerful tool for patients rebuilding their defenses after cancer treatment.
Ota K · 1991
AML patients who took bestatin 30 mg daily after achieving remission with chemotherapy stayed cancer-free much longer than those on placebo. The peptide worked by cranking up production of IL-1 and IL-2, the chemical messengers that rev up immune cells to attack any remaining cancer cells.
Tian W, Jiang X, Tamosiuniene R, et al. · 2013
Scientists discovered bestatin blocks an enzyme that creates leukotriene B4, a powerful inflammation-causing chemical that damages lung blood vessels. This anti-inflammatory action opened up a completely new use for bestatin: potentially treating pulmonary arterial hypertension, a serious lung disease where inflammation scars the arteries.
Umezawa H, Aoyagi T, Suda H, Hamada M, Takeuchi T · 1976
The original 1976 discovery report in the Journal of Antibiotics: bestatin isolated as an inhibitor of aminopeptidase B from actinomycete culture.
Eiger BioPharmaceuticals · 2016
Completed Phase 2 randomized placebo-controlled trial of ubenimex in pulmonary arterial hypertension, sponsored by Eiger BioPharmaceuticals.
Eiger BioPharmaceuticals · 2016
Completed Phase 2 trial of ubenimex in lower-limb lymphedema, sponsored by Eiger BioPharmaceuticals.
Eiger BioPharmaceuticals (PR Newswire) · 2015
Sponsor announcement: FDA granted orphan drug designation to ubenimex for the treatment of PAH on November 30, 2015. States ubenimex is a dual inhibitor of aminopeptidase and LTA4 hydrolase, used for over 25 years in Japan and marketed by Nippon Kayaku as Bestatin.
Nippon Kayaku Co., Ltd. · 2026
Official Japanese label: indicated for extension of survival in adult acute non-lymphocytic leukemia in combination with maintenance-intensification chemotherapy after complete remission induction; 30 mg ubenimex orally once daily. Listed adverse reactions (≤5% or frequency unknown) include nausea/vomiting, anorexia, abdominal pain, diarrhea, rash/erythema, pruritus, and AST/ALT elevations.
Head to head
Bestatin (Ubenimex) compared
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The complete Bestatin (Ubenimex) research profile: mechanism of action, clinical studies, effectiveness timeline, and FAQ.